package leetcode.tree_problem;

/**
 * 572. 另一棵树的子树
 * https://leetcode-cn.com/problems/subtree-of-another-tree/
 */
public class IsSubtree {
    public boolean isSubtree(TreeNode root, TreeNode subRoot) {
        if (root == null && subRoot == null){
            return true;
        }
        if (root == null || subRoot == null){
            return false;
        }
        //当这两个树相同，或者左子树包含，或右子树包含
        return isSameTree(root , subRoot) || isSubtree(root.left , subRoot) || isSubtree(root.right , subRoot);
    }
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if (p == null && q == null){
            return true;
        }
        if (p == null || q == null){
            return false;
        }
        if (p.val != q.val){
            return false;
        }
        return isSameTree(p.left , q.left) && isSameTree(p.right , q.right);
    }
}
